CWF B-3 DESIGN ANALYSIS - Appendix E.8.pdf

Record of Decision

FDEP FACID #168521650 Sites:

Storage Tank Site 16 (TU013) November 6, 1995 (Non-Program) Storage Tank Site 23 (TU018) & 24 (TU017) October 6, 1995 (Non-Program)

Final

Florida Air National Guard Jacksonville International Airport

Jacksonville, Florida

Prepared By

Air National Guard Headquarters Joint Base Andrews, Maryland

May 2022

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Final Record of Decision i Florida Air National Guard Base, Jacksonville, FL May 2022

Table of Contents 1 Declaration ...................................................................................................................... 1-1

1.1 Site Names and Location ........................................................................................... 1-1

1.2 Statement of Basis and Purpose ................................................................................. 1-1

1.3 Assessment of Sites ................................................................................................... 1-1

1.3.1 Site Assessment of UST-16 ............................................................................... 1-1

1.3.2 Site Assessment of UST-23 and UST-24 ........................................................... 1-2

1.4 Description of Selected Remedy................................................................................ 1-3

1.4.1 UST-16 ............................................................................................................. 1-3

1.4.2 UST-23 and UST-24 .......................................................................................... 1-5

1.5 Statutory Determinations ........................................................................................... 1-5

1.6 Data Certification Checklist ...................................................................................... 1-6

1.7 Authorizing Signatures .............................................................................................. 1-7

2 Decision Summary .......................................................................................................... 2-1

2.1 Site Name, Location, and Description ....................................................................... 2-1

2.2 Site History and Characterization Activities .............................................................. 2-1

2.2.1 UST-16 ............................................................................................................. 2-1

2.2.2 UST-23 and UST-24 .......................................................................................... 2-2

2.3 Community Participation .......................................................................................... 2-3

2.4 Site Characteristics .................................................................................................... 2-4

2.4.1 Physiography and Climate ................................................................................. 2-4

2.4.2 Geology/Hydrology ........................................................................................... 2-5

2.5 Nature and Extent of Contamination ......................................................................... 2-5

2.5.1 UST-16 ............................................................................................................. 2-5

2.5.2 UST-23 and UST-24 .......................................................................................... 2-6

2.6 Summary of Site Risks .............................................................................................. 2-7

2.6.1 Summary of Human Health Risk Assessment .................................................... 2-7

2.6.2 Summary of COCs ............................................................................................ 2-8

2.6.3 Basis for Action ................................................................................................. 2-8

2.7 Remedial Action Objectives ...................................................................................... 2-8

2.8 Description of Remedial Alternatives ........................................................................ 2-9

2.8.1 UST-16 Remedial Alternatives Evaluated in FFS .............................................. 2-9

2.8.2 UST-23 and UST-24 Remedial Alternatives Evaluated in the FFS ................... 2-10

2.9 Comparative Analysis ............................................................................................. 2-10

2.9.1 UST-16 Comparative Analysis ........................................................................ 2-11

2.9.1.1 Overall Protection of Human Health and the Environment ........................ 2-11

2.9.1.2 Compliance with ARARs .......................................................................... 2-11

2.9.1.3 Long-term effectiveness and permanence .................................................. 2-11

2.9.1.4 Reduction of toxicity, mobility, or volume through treatment .................... 2-11

2.9.1.5 Short-term effectiveness............................................................................ 2-14

2.9.1.6 Implementability ....................................................................................... 2-14

2.9.1.7 Cost .......................................................................................................... 2-14

2.9.2 UST-23 and UST-24 ........................................................................................ 2-14

2.9.2.1 Overall Protection of Human Health and the Environment ........................ 2-14

2.9.2.2 Compliance with ARARs .......................................................................... 2-15

2.9.2.3 Long-term effectiveness and permanence .................................................. 2-15

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2.9.2.4 Reduction of toxicity, mobility, or volume through treatment .................... 2-16

2.9.2.5 Short-term effectiveness............................................................................ 2-16

2.9.2.6 Implementability ....................................................................................... 2-16

2.9.2.7 Cost .......................................................................................................... 2-16

2.10 Selected Remedy ................................................................................................. 2-17

2.10.1 UST-16 Excavation with Offsite Disposal to Attain Residential SCTLs ........... 2-17

2.10.2 UST-23 and UST-24 In-Situ Bioremediation, NAM, and ICs .......................... 2-18

2.11 Statutory Determinations ..................................................................................... 2-18

2.11.1 Chemical-Specific Requirements ..................................................................... 2-19

2.11.1.1 Soil Chemical-Specific Requirements ....................................................... 2-19

2.11.1.2 Groundwater Chemical-Specific Requirements ......................................... 2-19

2.11.2 Action-Specific Requirements ......................................................................... 2-19

2.11.3 RCRA ............................................................................................................. 2-19

2.11.4 OSHA ............................................................................................................. 2-20

2.11.5 Ambient Water Quality Criteria ....................................................................... 2-20

2.11.6 Land Use Controls ........................................................................................... 2-20

2.11.7 Location-Specific Requirements ...................................................................... 2-20

2.11.8 Endangered Species Act .................................................................................. 2-21

2.11.9 Federal Clean Water Act of 1972 ..................................................................... 2-21

2.11.10 Utilization of Permanent Solutions and Alternative Treatment Technologies ... 2-21

2.11.11 Preference for Treatment as a Principal Element .............................................. 2-21

2.11.12 Five-Year Review Requirements ..................................................................... 2-21

2.12 Documentation of Significant Changes ................................................................ 2-22

2.13 Responsiveness Summary.................................................................................... 2-22

2.14 References ........................................................................................................... 2-23

Tables Table 2-1. Public Notification of Document Availability ......................................................... 2-3 Table 2-2. Public Comment Period Requirements ................................................................... 2-4 Table 2-3. Comparative Analysis of Remedial Action Alternatives for UST-16 ..................... 2-12 Table 2-4. Comparative Analysis of Remedial Action Alternatives for UST-23 and UST-24 . 2-13 Table 2-5. Cost Summary of Remedial Action Alternatives for UST-16 ................................ 2-15 Table 2-6. Cost Summary of Remedial Action Alternatives for UST-23 and UST-24 ............ 2-17

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May 2022

Attachments

Attachment 1 – Figures.

Figure 1-1 Florida Air National Guard Base Location Figure 1-2 Location Map for UST-16, UST-23, and UST-24 Figure 1-3 Soil Sample Results for PAHs at UST-16 Figure 1-4 Soil Sample Results for Lead at UST-16 (TU013) Figure 1-5 Detected Constituents in Soil at UST-23, and UST-24 Figure 1-6 Groundwater Sample Results for VOCs and TPH at UST-23 and UST-24 Figure 1-7 Extent of Soil Excavation to Attain Residential SCTLs at UST-16

Attachment 2 – Notice of Availability of Proposed Plans for UST Site 16 (TU013) and co-located UST-23 (TU018) and 24 (TU017).

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May 2022

Acronyms

AMSL above mean sea level ANG Air National Guard ARAR Applicable or Relevant and Appropriate Requirement A4VR Environmental Division Restoration Branch B(a)P Benzo(a)pyrene BGS below ground surface CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations COC contaminants of concern DoD Department of Defense EC engineering control EDB 1,2-dibromoethane EQ equivalent EQD Environmental Quality Division EPA Environmental Protection Agency FAC Florida Administrative Code FDEP Florida Department of Environmental Protection FFS Focused Feasibility Study FLANG Florida Air National Guard FLANGB Florida Air National Guard Base FW fighter wing GCTL groundwater cleanup target level HHRA human health risk assessment IAP International Airport IC institutional control ID identification IRP Installation Restoration Program LUC land use control MCL maximum contaminant level mg/kg milligrams per kilogram NAM natural attenuation monitoring NCP National Oil and Hazardous Substances Pollution Contingency Plan NFA no further action NGB National Guard Bureau O&M operations and maintenance OSHA Operational Safety and Health Administration PAH polycyclic aromatic hydrocarbon PCB polychlorinated biphenyl PP Proposed Plan RAO remedial action objective RCRA Resource Conservation and Recovery Act RI Remedial Investigation ROD Record of Decision RSL residential screening level

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May 2022

Acronyms (continued)

SAR Site Assessment Report SCTL soil cleanup target level SARA Superfund Amendments and Reauthorization Act SPLP synthetic precipitation leaching procedure SVOC semi-volatile organic compounds TBC to be considered TPH total petroleum hydrocarbons TRPH total recoverable petroleum hydrocarbons µg/L micrograms per liter USAF United States Air Force UST underground storage tank UU/ UE unlimited use/unrestricted exposure VOC volatile organic compounds

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Final Record of Decision 1-1

May 2022

1 Declaration

1.1 Site Names and Location

Facility Name: Florida Air National Guard Base (FLANGB)

Site Location: Jacksonville, Florida Florida Department of Environmental Protection (FDEP) Florida Administrative Code (FAC) Identification (ID) Number: 168521650 Storage Tank Site 16 (TU013) November 6, 1995 (Non-Program)

Storage Tank Site 23 (TU018) & 24 (TU017) October 6, 1995 (Non-Program)

1.2 Statement of Basis and Purpose

This decision document presents the selected remedy for the preferred alternative for cleanup of contaminants at underground storage tank (UST) Site 16 (TU013) and co-located UST Site 23 (TU018) and UST Site 24 (TU017) at the FLANGB. Sites 16, 23, and 24 are referred to as UST- 16, UST-23, and UST-24, respectively, throughout the remainder of this document. The FLANGB is located adjacent to the Jacksonville International Airport (IAP). The FLANGB and the locations of UST-16, UST-23, and UST-24 at the FLANGB are shown on Figure 1-1 and Figure 1-2. All of the figures referenced in this document are provided in Attachment 1.

This document is issued by the Air National Guard (ANG) as the lead agency. The ANG is managing remediation of contamination at UST-16 and co-located UST-23 and UST-24 in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended by the Superfund Amendments and Reauthorization Act (SARA), and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), as required by the Department of Defense (DoD) Installation Restoration Program (IRP) at the FLANGB.

ANG has been assigned by the United States Air Force (USAF) as the lead agency responsible for the implementation of the IRP program at the FLANGB in Jacksonville, with regulatory oversight by the FDEP and City of Jacksonville Environmental Quality Division (EQD). The EQD is currently contracted to lead the regulation of contaminated site cleanup at these sites under Chapter 62-780 of the FAC by the FDEP. As the lead agency, the ANG has selected the remedy at UST- 16 and co-located UST-23 and UST-24 with regulatory and public input. The remedy at each site is detailed in a Proposed Plan (PP) (ANG, 2020) that was approved by the EQD on August 30, 2019 (EQD, 2019).

The overall objective of the project is to achieve a result protective of human health and the environment that that will support a Site Rehabilitation Completion Order (SRCO) at UST-16 and co-located UST-23 and UST-24 with no institutional controls (ICs) or risk reclassification per

FAC.

1.3 Assessment of Sites

1.3.1 Site Assessment of UST-16

Site assessment activities conducted in 2011 included the collection of five soil samples and one groundwater sample (ANG, 2012). Soil samples were analyzed for volatile organic contaminants (VOCs), semi-volatile organic contaminants (SVOCs), total recoverable petroleum hydrocarbons (TRPH), polychlorinated biphenyls (PCBs), and select metals (i.e., arsenic, lead, cadmium, and

Final Record of Decision 1-2

May 2022 chromium). The groundwater sample was analyzed for VOCs, SVOCs, 1,2-dibromoethane (EDB), total petroleum hydrocarbons (TPH), PCBs, and select metals (i.e., arsenic, lead, cadmium, and chromium). The site assessment concluded that one soil sample exceeded the Environmental Protection Agency (EPA) soil screening level for leachability of lead to groundwater. The polycyclic aromatic hydrocarbon (PAH) benzo(a)pyrene (B(a)P) and calculated B(a)P equivalent (EQ) in one soil sample exceeded the Florida direct-exposure soil cleanup target level (SCTL). No constituents were detected in groundwater above Florida groundwater cleanup target levels (GCTLs). Based on the site assessment findings, additional soil and groundwater sampling was conducted in a Remedial Investigation (RI) in 2014 and a Supplemental RI in 2015 to delineate the horizontal and vertical extents of lead and PAHs in soil and to further assess lead in groundwater. A site-specific lead SCTL of 49.8 milligrams per kilograms (mg/kg) for soil leachability to groundwater was developed in accordance with FDEP guidance at that time (ANG, 2016).

The RI results concluded that lead and the PAHs B(a)P and benzo[a]anthracene were the only analytes detected in soil above the SCTLs for leachability to groundwater. No chemicals were detected in groundwater in a temporary monitoring well (T16-TW1) above GCTLs; however, because of the elevated lead results detected in soil, it was recommended that permanent monitoring wells be installed and sampled for lead. Two shallow (T16-MW2 and T16-MW3) and two deep (T16-MW1 and T16-MW4) monitoring wells were installed and sampled to further assess lead in groundwater. Lead was not detected in any of the groundwater samples collected from the wells at UST-16.

In summary, analysis of the sample data concluded that PAHs, specifically B(a)P and B(a)P EQ, were Human Health Contaminants of Concern (COCs) in soil. No other human health COCs were identified in soil or groundwater. Lead, B(a)P, and benzo[a]anthracene in soil were identified above the SCTLs for leachability to groundwater. The locations of PAH exceedances in soil are shown on Figure 1-3. The locations of lead exceedances in soil are shown on Figure 1-4.

A Focused Feasibility Study (FFS) for UST-16 was finalized in April 2017 (ANG, 2017). The purpose of the FFS was to evaluate the COCs and cleanup goals and to evaluate remedial alternatives. Based on a comparative analysis of alternatives, excavation with offsite disposal to attain residential SCTLs (Alternative 4) was recommended in the FFS for UST-16.

1.3.2 Site Assessment of UST-23 and UST-24

UST Removal activities in 1995 included a limited source (soil) removal along with the USTs.

During the 2011 site investigation, soil samples were collected at depths ranging from 2 to 6 feet below ground surface (BGS) and analyzed for benzene, toluene, ethylbenzene, xylene, TPH, and PAHs. As shown on Figure 1-5, none of the detected constituents exceeded SCTLs for unrestricted direct exposure or leachability to groundwater (ANG, 2012).

During the 2011 site investigation, benzene and TPH were detected in groundwater above the GCTLs. In subsequent RI activities, groundwater samples from vertical profile borings also exhibited benzene and TPH detections above GCTLs. However, groundwater samples collected from the permanent monitoring wells in 2014 and 2015 exhibited only benzene exceedances above GCTLs in one shallow well (T23/24-MW5) and isopropylbenzene exceedances above the GCTL in one deep well (T23/24-MW3) and one shallow well (T23/24-MW5) (ANG, 2016). The monitoring wells and locations of exceedances of the GCTLS are identified on Figure 1-6.

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May 2022

A FFS for UST-23 and UST-24 was finalized in April 2017 (ANG, 2017). The purpose of the FFS was to evaluate the COCs and cleanup goals and to evaluate remedial alternatives. Based on a comparative analysis of alternatives, groundwater sampling for natural attenuation monitoring (NAM) of benzene and isopropyl benzene with ICs (Alternative 3) was recommended at UST-23 and UST-24 in the FFS.

Subsequent to the FFS, further ANG analysis of Alternative 3 and Alternative 4 (NAM, in-situ bioremediation, and ICs) found that Alternative 4 provided a more conservative approach to attain the RAOs at UST-23 and UST-24 with a minimal capital cost increase. Alternative 4 is the same as Alternative 3, except for the addition of in-situ groundwater bioremediation. The in-situ bioremediation provided in Alternative 4 offers more certainty in attaining the RAOs in a shorter remedial timeframe. Therefore, NAM, in-situ groundwater bioremediation, and ICs (Alternative

4) were selected as the more conservative remedy at UST-23 and UST-24.

1.4 Description of Selected Remedy

1.4.1 UST-16

Remedial alternatives for UST-16 were developed and evaluated through an FFS (ANG, 2017).

Based on a comparative analysis of remedial alternatives, the excavation with offsite disposal to attain residential soil SCTLs, Alternative 4, was recommended for UST-16. Alternative 4 meets the remedial action objectives (RAOs) for UST-16 and provides the best balance of cost and overall protection, while providing an effective, long-term solution. Under this proposed alternative, all contaminated soil with COC concentrations (i.e., PAH concentrations) exceeding residential SCTLs will be excavated and disposed offsite. The excavation will be backfilled with clean native fill material and seeded with grass cover to restore the excavated area to the surrounding site conditions. There will be no operations and maintenance (O&M) activities or five-year CERCLA reviews necessary under this alternative because the remedial action will attain SCTLs protective of residential land use conditions.

Following approval of the ANG 2017 FFS and recommended alternative, a project review meeting was conducted with ANG, FLANG, and the City of Jacksonville EQD regulator in November 2017. During this meeting, it was recommended by the project team that, prior to implementation of remedial Alternative 4, an option be considered to analyze lines of evidence that PAHs detected in soil at UST-16 are related to background sources and not UST-16. In addition, it was recommended that lead leachability in soil at UST-16 be analyzed by synthetic precipitation leaching procedure (SPLP) to confirm whether lead is at concentrations capable of leaching from the soil to groundwater and that a confirmation groundwater sample be sampled from the 4 existing monitoring wells to demonstrate lead continues to be below GCTLs. The project team agreed that successful demonstration of PAHs related to background, SPLP soil lead results less than the lead leachability criteria (49.8 mg/kg), and groundwater lead concentrations less than the GCTL could be an acceptable method of achieving no further action (NFA) for UST-16 as an option to Alternative 4. The PAH background analysis, soil lead SPLP analysis, and groundwater analysis and remedial Alternative 4 are detailed in the EQD approved PP (ANG, 2020).

The optional analysis to demonstrate NFA criteria (background analysis, SPLP soil lead analysis, and sampling four existing monitoring wells) and Alternative 4 (excavation with offsite disposal to attain residential SCTLs) are briefly summarized in the following sections.

UST-16 Background Analysis – UST-16 PAH Analysis of Background and Site Soil. An analysis of the PAH concentrations and distribution in soil at UST-16 and background should be conducted

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May 2022 utilizing the methods in the FDEP technical document entitled Guidance for Comparing Background and Site Chemical Concentrations in Soil (FDEP, 2012). Lines of evidence that the PAHs, B(a)P, and B(a)P EQs, which exceed SCTLs, are associated with background sources will be reviewed.

UST-16 SPLP Soil Analysis – Several groundwater analytical results to date have not detected lead in groundwater above GCTLs; therefore, soil with lead detected above the leaching to groundwater criteria does not appear to be leaching to groundwater. To demonstrate this result, a soil sample should be taken in the soil adjacent to previous soil sample T16-HA13, which exceeded lead leachability criteria, and analyzed for lead by SPLP utilizing EPA Method 1312.

UST-16 Groundwater Analysis – A groundwater sample should be collected from the 4 existing wells at UST-16. The samples should be analyzed for lead only, as there are no COCs in groundwater, and lead was previously detected in soil above the leachability criteria.

The analysis will be provided in a report to be submitted to EQD and titled Post Active Remedial Monitoring Report – Site Rehabilitation Recommendation Request. Should these analyses be unsuccessful in demonstrating NFA criteria, the 2017 FFS remedial alternative, excavation with offsite disposal to attain residential SCTLs, will be implemented at UST-16.

Demonstration and regulatory approval that PAHs in soil are associated with background concentrations and not site derived, SPLP soil results are less than the lead leachability criteria, and groundwater results are below lead GCTLs, would result in NFA and an SRCO at UST-16.

Because the SRCO would attain unlimited use and unrestricted exposure (UU/UE) status, CERCLA five-year reviews would not be required following the SRCO approval.

Alternative 4 - UST-16 Excavation with Offsite Disposal to Attain Residential SCTLs – This alternative will be implemented, if warranted, based on the results of the optional background, SPLP, and groundwater analysis described above. Under Alternative 4, soil excavation will be conducted from 0 to 1 feet BGS for an area of approximately 970 square feet that exceeds the direct-contact residential SCTLs for PAHs. The entire area exceeding the soil lead and PAH leachability SCTL is also encompassed within this soil excavation. A deeper zone (0 to 4 feet BGS) will also be excavated for an area approximately 25 square feet at soil sample location T16- HA1, where the PAH (benzo(a)anthracene) concentration exceeded the direct-contact SCTL. The proposed area to be excavated is shown on Figure 1-7. EQD has recommended that confirmatory soil sampling for PAHs and lead by laboratory analyses be conducted along the sidewalls and the bottom of excavations in accordance with FDEP regulations. The confirmatory soil samples should be collected from the sidewall and bottom of the excavation in twenty-foot intervals. During excavation activities, the existing monitoring wells at the site should be protected, and soil should be excavated around the wells in a manner that does not damage the wells. One representative groundwater sampling event is required at source removal sites, such as UST-16, that did not historically yield groundwater contamination, in accordance with FDEP Petroleum Restoration Program Closure Guidelines dated January 27, 2014 (EQD, 2017).

The excavated soil (approximately 40 cubic yards) will be appropriately characterized and disposed at an offsite facility. Based on historical soil concentrations at UST-16, it is anticipated that the excavated soil will be classified as non-hazardous waste. The excavation will be backfilled with clean native soil material obtained either from an on-base location or locally sourced from an offsite location. The backfilled area will be brought to grade and seeded with grass cover to match the surrounding cover at UST-16. Following site restoration, a Corrective Action Completion Report will be submitted to EQD for review and approval. It is anticipated that a SRCO would be

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May 2022 issued by EQD. Because this alternative would attain UU/UE status, CERCLA five-year reviews would not be required.

1.4.2 UST-23 and UST-24

Remedial alternatives for UST-23 and UST-24 were developed and evaluated in the 2017 FFS (ANG, 2017). Based on a comparative analysis of remedial alternatives, Alternative 3 was recommended for implementation at UST-23 and UST-24. Subsequent to the FFS and the PP, further ANG analysis of Alternative 3 and Alternative 4 (NAM, in-situ bioremediation, and ICs) found that Alternative 4 provided a more conservative approach to attain the RAOs at UST-23 and UST-24 with a minimal capital cost increase. Alternative 4 is the same as Alternative 3, except for the addition of in-situ bioremediation. The groundwater in-situ bioremediation provided in Alternative 4 offers more certainty in attaining the RAOs in a shorter remedial timeframe.

Therefore, NAM, in-situ bioremediation, and ICs (Alternative 4) were selected as a more conservative remedy at UST-23 and UST-24. Alternative 4 meets the RAOs for UST-23 and UST- 24 and provides the best balance of cost and overall protection while providing an effective, long-term solution. Alternative 4 consists of groundwater in-situ bioremediation applications, groundwater sampling for NAM of benzene and isopropyl benzene at the six existing monitoring wells at UST-23 and UST-24, and ICs until benzene and isopropyl benzene are below GCTLs.

The groundwater sampling will be performed on a quarterly basis for the first year, semi-annually for the second year, and annually thereafter, as required. The RAOs are to reduce benzene and isopropyl benzene concentrations below the GCTLs of 1 and 0.8 micrograms per liter (µg/L), respectively. The ICs would be implemented to restrict groundwater use until benzene and isopropyl benzene concentrations in groundwater are attained below the GCTLs. The ICs would limit use of the site to industrial/commercial purposes and prohibit the installation of water wells for any use, including use as a water supply. Given that the benzene and isopropyl benzene concentrations are currently only slightly above the GCTLs, it is anticipated that contaminant concentrations would attenuate below GCTLs in a relatively short time through groundwater in-situ bioremediation and NAM. Two consecutive groundwater sampling events with benzene and isopropyl benzene results below GCTLs will be required to ensure compliance in accordance with FDEP guidelines.

Following demonstration of site restoration, a Corrective Action Completion Report will be submitted to EQD for review and approval. It is anticipated that an SRCO would be issued by EQD at that time.

1.5 Statutory Determinations

The selected remedy for UST-16 and UST-23 and UST-24 is protective of human health and the environment, complies with promulgated requirements that are applicable or relevant and appropriate (ARARs) to the remedial action, and is cost effective.

The selected remedy at each site represents the maximum extent to which permanent solutions can be used in a practicable manner at the site. It provides the best balance or trade-offs in terms of balancing criteria while also considering the bias against offsite treatment and disposal and considering regulatory and community acceptance. The NCP establishes the expectation that treatment will be used to address the principal threats posed by a site whenever practicable (40 Code of Federal Regulations [CFR] 300.430[a] [1] [iii] [A]).

At UST-16, Alternative 4, soil excavation and off-site disposal to residential criteria, would satisfy the statutory preference for treatment as a principal element of the remedy (i.e., reduces the

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May 2022 toxicity, mobility, or volume of hazardous substances, pollutants, or contaminants as a principal element through treatment). Because the remedy UST-16 will not result in hazardous substances, pollutants, or contaminants remaining on-site above levels that allow for UU/UE, a five-year review would not be required for UST-16. As discussed in Section 4.1.1, Alternative 4 will be implemented based on the results of an optional background, SPLP, and groundwater analysis to confirm the remedial alternative is warranted at this site.

At UST-23 and UST 24, it is anticipated that groundwater in-situ bioremediation and NAM will result in benzene and isopropyl benzene concentrations to attenuate below GCTLs in a relatively short period of time. ICs will be implemented to restrict groundwater use until benzene and isopropyl benzene concentrations in groundwater are recorded below the GCTLs. The ICs would prevent unacceptable exposure to receptors by limiting the use of the site to industrial/commercial purposes and prohibit the installation of water wells for any use, including use as a water supply.

1.6 Data Certification Checklist

The following information is included in the Decision Summary section of this Record of Decision (ROD) (Section 2). Technical documents with additional information can also be found in the Administrative Record for UST-16, UST-23, and UST-24, available online at https://ar.afcec-cloud.af.mil/, and also available for review at the Highlands Branch Public Library located at 1826 Dunn Avenue, Jacksonville, FL. Historical documents in the Administrative Record can be requested by contacting the ANG Program Manager, Mr. Mark Dickerson, at mark.dickerson@us.af.mil.

List of COCs and their respective concentrations.

Cleanup levels established for COCs and the basis for these levels.

Potential land and ground water use that will be available at the site as a result of the selected remedy.

Estimated capital, annual operation and maintenance, and total present worth costs, discount rate, and the number of years over which the remedy cost estimates are projected.

Key factor(s) that led to selecting the remedy (i.e., describe how the selected remedy provides the best balance of tradeoffs with respect to the balancing and modifying criteria, highlighting criteria key to the decision).

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May 2022

1.7 Authorizing Signatures

This signature sheet documents the ANG approval, and concurrence of Florida ANG (FLANG) and the City of Jacksonville EQD.

Elaine Magdinec, PE, GS-15 Date Chief, Environmental Division

NGB/A4V

Stephanie M. Moronta, E.I. Date Environmental Associate Engineer City of Jacksonville / Neighborhoods Department 214 N. Hogan Street, 5th floor, Jacksonville, FL 32202

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May 2022

2 Decision Summary The decision summary identifies the selected remedy, explains how the remedy fulfills statutory and regulatory requirements, and provides a substantive summary of the Administrative Record file that supports the remedy selection decision.

2.1 Site Name, Location, and Description

The FLANGB is located in the northeast coastal region of Florida, approximately ten miles north of the City of Jacksonville, Duval County, and is adjacent to the Jacksonville IAP. The location of FLANGB is shown on Figure 1-1. The FLANGB includes approximately 30 buildings and occupies approximately 332 acres of land. The base is fenced, with only one access point at the main gate, which is guarded by base security forces.

The FLANGB supports the 125th Fighter Wing (FW). The mission of the 125th FW is to maintain a combat-ready response team and to intercept unidentified aircraft approaching US airspace from the east and southeast. Currently, the 125th FW maintains F-15 Eagle fighters on continuous 24-hour alert status. UST-16, UST-23, and UST-24 are located in the central portion of the FLANGB property. UST-16 consisted of a former oil and water separator that was removed on November 6, 1995. UST-23 and UST-24 consisted of two former unleaded gasoline USTs that were co-located and removed at the same time on October 4, 1995. The locations of UST-16, UST-23, and UST- 24 are illustrated on Figure 1-2.

2.2 Site History and Characterization Activities

This section provides background information and summarizes the series of previous site activities and investigations at UST-16, UST-23, and UST-24 that led to the ROD. This section also describes the CERCLA response actions undertaken at UST-16, UST-23, and UST-24.

2.2.1 UST-16

Site Assessment: During the 2011 site investigation, five soil samples were analyzed for VOCs, SVOCs, TPH, PCBs, and select metals (i.e., arsenic, lead, cadmium, and chromium), and one groundwater sample was analyzed for VOCs, SVOCs, EDB, TPH, PCBs, and select metals (i.e., arsenic, lead, cadmium, and chromium). One soil sample exceeded the EPA soil screening level for leachability. No constituents were detected in groundwater above the GCTLs. Based on the findings in the Site Assessment Report (SAR), additional soil and groundwater samples were recommended to evaluate the horizontal and vertical extents of lead (ANG, 2012). Based on the EQD review of the SAR, it was determined that the calculated B(a)P equivalent in one sample from location T16-HA1 (3 to 4 feet BGS) also exceeded the direct-exposure SCTL, and that a site-specific lead SCTL for groundwater leachability had not been determined for screening (ANG, 2012).

RI field activities were conducted from September to December 2014 to delineate the PAH contamination in soil and the lead contamination in soil and groundwater and to calculate a site-specific lead SCTL for groundwater leachability.

Supplemental RI field activities (PAH and lead soil sampling) were conducted in October and December 2015 to complete the objectives for the RI. At UST-16, seven soil borings were used

Final Record of Decision 2-2

May 2022 to delineate the horizontal and vertical extents of lead contamination in soil above SCTLs. In addition, five soil borings were used to delineate the horizontal and vertical extents of PAH contamination in soil at UST-16 based on SCTLs. The horizontal and vertical extents of lead in groundwater at UST-16 were delineated based on GCTLs with two shallow monitoring wells and two deep monitoring wells.

Remedial alternatives for UST-16 were developed and evaluated through the FFS (ANG, 2017). Based on a comparative analysis of remedial alternatives, Alternative 4, excavation with offsite disposal to attain residential soil SCTLs was recommended for UST-16. This remedial excavation alternative will be implemented, if required, subsequent to a background analysis of PAH concentrations and site soil, SPLP soil lead analysis, and one round of groundwater analysis for lead at the four existing monitoring wells at UST-16. The successful demonstration of PAHs at background concentrations, SPLP soil lead results less than the lead leachability criteria (49.8 mg/kg), and groundwater lead concentrations less than the GCTL, would be an acceptable method of achieving NFA for UST-16 as an option prior to implementation of Alternative 4.

2.2.2 UST-23 and UST-24

2011 Site Assessment: During this investigation, ten soil samples were analyzed for benzene, toluene, ethylbenzene, and xylenes; methyl tertiary butyl ether; PAHs; and TPH, and two groundwater samples were analyzed for VOCs, PAHs, EDB, TPH, and lead. In soil, none of the detected constituents exceeded SCTLs for residential direct exposure or groundwater leachability; however, benzene and TPH were detected in groundwater above the GCTLs.

Based on the findings in the SAR, installation of additional monitoring wells was recommended to evaluate the horizontal and vertical extents of the benzene and TPH groundwater plume. Jacksonville EQD approved the recommendation per the letter dated November 30, 2012 (EQD 2012).

2014 RI: The initial RI field activities were conducted from September to December 2014.

During the RI, four vertical profile borings were installed to help define the extent of benzene and TPH contamination in groundwater and to determine where permanent monitoring wells should be installed at this site. Based on the results of the vertical profile groundwater sampling, benzene was detected in the shallow and deep groundwater above GCTLs. As a result, a total of five permanent monitoring wells were installed in October 2014. Two of the monitoring wells (T23/24-MW3 and T23/24-MW4) were screened in the deep interval (approximately 15 to 25 feet BGS), and the remaining three wells (T23/24-MW1, T23/34- MW2, and T23/24-MW5) were screened in the shallow zone (approximately 5 to 15 feet BGS).

Each well was sampled in December 2014 and analyzed for benzene and TPH.

2015 Supplemental RI: Based on the initial RI results, supplemental field activities (well installation and groundwater sampling) were conducted in October and December 2015 to complete the objectives for the RI, as recommended by the stakeholders during quarterly status meetings held on April 21, 2015, and August 11, 2015. An additional round of groundwater samples from the five permanent wells was collected in October 2015 to confirm the initial groundwater sample results. Based on the October 2015 sampling results, one additional shallow monitoring well (T23/24-MW6) was installed in November 2015, and groundwater samples were collected for VOCs and TPH analyses. In addition, it was requested that the laboratory provide other VOC results for the initial rounds of sampling. Based on the two

Final Record of Decision 2-3

May 2022 rounds of sampling from the permanent monitoring wells installed during the RI field activities, benzene and isopropylbenzene are the only two constituents detected in groundwater above GCTLs. None of the other VOCs or TPH was detected in groundwater at UST-23 and UST-24 above GCTLs.

An FFS for UST-23 and UST-24 (ANG, 2017) was finalized in April 2017. The purpose of the FFS was to evaluate the COCs and cleanup goals and to evaluate remedial alternatives.

Based on ANG comparative analysis of the alternatives presented in the FFS, Alternative 4 (in-situ bioremediation of benzene and isopropyl benzene, NAM, and ICs) was selected at UST-23 and UST-24.

2.3 Community Participation

NCP Section 300.430(f) (3) establishes the public participation activities that the lead agency must conduct following preparation of the PP and review by the support agency. Components of these items and documentation of how each component was satisfied for UST-16, UST-23, and UST-24 are described in Tables 2-1 and Table 2-2 below.

Table 2-1. Public Notification of Document Availability

Requirement: Satisfied by:

Notice of availability of the PP must be made in a general circulation major local newspaper.

Notice of PP availability and 30-day public comment period from March 16 to April 14, 2020 were published in the legal notice section of the Florida Times-Union on March 9, 2020.

Notice of availability should consist of the following information:

Site name and location

Date and location of public meeting

Identification of lead and support agencies

Request for public comments

Public participation opportunities including:

– Location of information repositories and Administrative Record file

– Methods by which the public may submit written and oral comments, including a contact person

– Dates of public comment period

Notice of availability included all of these components and is included for reference as Attachment 2 to this ROD.

Final Record of Decision 2-4

May 2022

Table 2-2. Public Comment Period Requirements

Requirement: Satisfied by:

Lead agency should make document available to public for review on same date as newspaper notification.

The PP for UST-16. UST-23, and UST-24 was made available to the public on March 16, 2020 at the Highlands Branch Public Library in Jacksonville, FLA and online. The legal notice of the PP is provided as Attachment 2 to this ROD.

Lead agency must ensure that all information that forms the basis for selecting the response action is included as part of the Administrative Record file and made available to the public during the public comment period.

ANG headquarters located at Joint Base Andrews maintains the USAF Administrative Record file for UST-16, UST Site-23, and UST-24. All data collected and all CERCLA primary documents produced for UST-16, UST-23, and UST-24 are maintained as part of this file, which is available to the public online. A link to the USAF Administrative Record online database was provided in the legal notice and can be accessed at https://ar.afcec-cloud.af.mil.

CERCLA Section 117(a)(2) requires the lead agency to provide the public with a reasonable opportunity to submit written and oral comments on the PP.

NCP Section 300.430(f)(3)(i) requires the lead agency to allow the public a minimum of 30 days to comment on the RI/FS and the PP and other supporting information located in the administrative record and information repository.

The ANG provided a public comment period for the PP from March 16 to April 14, 2020.

The lead agency must extend the public comment period by at least 30 additional days upon timely request.

The ANG received no requests to extend the public comment period.

The lead agency must provide the opportunity for a public meeting to be held at or near the site during the public comment period. A transcript of this meeting must be made available to the public and be maintained in the Administrative Record and information repository for the site (pursuant to NCP Section 300.430(f)(3)(i)(E)).

No comments or requests for public meeting were received from the public during the public comment period; therefore, no public meeting was held.

2.4 Site Characteristics

2.4.1 Physiography and Climate

The FLANGB is co-located adjacent to the Jacksonville IAP in Jacksonville, Florida and is approximately ten miles north of the City of Jacksonville. The regional topography is influenced by a series of seven ancient marine terraces formed through successive incremental lowering of the sea level during Pleistocene glaciation. During each interim sea level change, a portion of the emerging sea floor was exposed as a level plain or terrace. Jacksonville is situated on the Wicomico terrace, 70 to 100 feet above mean sea level (AMSL), and it extends through south-central Duval County and western Nassau County into Georgia, trending parallel to the present Atlantic Ocean shoreline. The topography across the base and in its general vicinity displays very low relief, as the elevation of the ground surface is approximately 20 to 28 feet AMSL.

Final Record of Decision 2-5

May 2022

The Jacksonville area, which includes the FLANGB, is drained through the St. Johns and Nassau Rivers and their tributaries. The waters of the St. Johns River and the lower portion of its tributaries are impacted by tides throughout Duval County. Surface drainage is sluggish, and the streams form a dendritic pattern in the flat, marshy areas surrounding the Jacksonville IAP. Cedar Creek is the nearest major drainage feature to the Base. Several unnamed tributaries drain the Base and discharge to Cedar Creek. The waters of Cedar Creek flow in a southeasterly direction and discharge into the Broward River, which discharges into the St. Johns River.

2.4.2 Geology/Hydrology

The regional geology of northeast Florida consists primarily of Eocene limestone (Ocala Group, Avon Park Limestone and Lake City Limestone) overlain by the Hawthorn Group, which consists of interbedded sand, clay, shale, and silty limestones. The soil types include:

• Lake City Limestone – alternating beds of lignite, chalky to granular limestone and massive to finely crystalline dolomite.

• Avon Park Limestone – overlies the Lake City Limestone in northeast Florida and the unit has been considerably thinned by erosion to approximately 50 feet in thickness in the study area.

• Ocala Group – subdivided into three carbonate sub-formations, which all consist of fragmental marine limestones and distinguished by slight changes in lithology and fossil content.

• Hawthorn Group – overlies the Ocala Group, filling erosional depressions in the surface of the Ocala Group.

• Upper Miocene or Pliocene deposits – overlies the Hawthorn group, occasionally exposed at the surface in deep road cuts or banks of the incised rivers.

In northeast Florida, groundwater occurs in two separate hydrogeologic systems: the deeper Floridian Aquifer system and a shallow aquifer that includes the water table.

Shallow surficial aquifer – situated above the Floridian aquifer and is composed of unconsolidated sediments such as limestones, shales and sands. This aquifer includes the water table, which is encountered at approximately 5 feet BGS and fluctuates with rainfall. The aquifer is primarily recharged through slow infiltration of rainfall, and regional groundwater flow is generally to the east-southeast, with localized variation (often to the northwest and west) in the northern portion of the base due to a small mound in the middle of the installation and variations in rainfall.

Floridian Aquifer system–artesian aquifer that begins at approximately 475 feet BGS at the installation and includes multiple water bearing formations: the Ocala group, the Lake City limestone and the Oldsmar limestone. This Aquifer system provides the major source of potable water for the Jacksonville area and the installation.

2.5 Nature and Extent of Contamination

2.5.1 UST-16

UST-16 site assessment activities conducted in 2011 included the collection of five soil samples and one groundwater sample. Soil samples were analyzed for VOCs, SVOCs, TRPH, PCBs, and select metals (i.e., arsenic, lead, cadmium, and chromium). The groundwater sample was analyzed

Final Record of Decision 2-6

May 2022 for VOCs, SVOCs, EDB, TPH, PCBs, and select metals (i.e., arsenic, lead, cadmium, and chromium). The site assessment concluded that one soil sample exceeded the EPA soil screening level for leachability of lead to groundwater and that the PAH constituent, B(a)P, and calculated B(a)P EQ in one soil sample exceeded the Florida SCTL. No constituents were detected in groundwater above Florida GCTLs.

Based on the site assessment findings, additional soil and groundwater sampling was conducted in RI activities in 2014 and 2015 to delineate the horizontal and vertical extents of lead and PAHs in soil and to lead in groundwater. A site-specific lead SCTL of 49.8 mg/kg for soil leachability to groundwater was developed in accordance with FDEP guidance at that time (ANG, 2016).

The 2014 RI results concluded that lead and the PAHs B(a)P and benzo[a]anthracene were the only analytes detected in soil above the SCTLs for leachability to groundwater. No chemicals were detected in groundwater in a temporary monitoring well (T16-TW1) above GCTLs; however, because of the lead leachability exceedance in soil, it was recommended that permanent monitoring wells be installed and sampled for lead. Two shallow (T16-MW2 and T16-MW3) and two deep (T16-MW1 and T16-MW4) monitoring wells were installed and sampled to further assess lead in groundwater. Lead was not detected in any of the groundwater samples collected from the wells at UST-16.

In summary, analysis of the sample data concluded that PAHs, specifically B(a)P and B(a)P EQ.

were potential human health COCs in soil; no other human health COCs were identified in soil or groundwater. Lead, B(a)P, and benzo[a]anthracene in soil were identified above the SCTLs for leachability to groundwater. The locations of B(a)P and B(a)P EQ exceedances in soil are shown on Figure 1-3. The locations of lead exceedances in soil are shown on Figure 1-4.

An FFS for UST-16 was finalized in April 2017 (ANG, 2017). The purpose of the FFS was to evaluate the COCs, cleanup goals,…